Absorption, distribution, metabolism, excretion and toxicity of microplastics in the human body and health implications

Unraveling microplastic behavior in simulated digestion: Methods, insights, and standardization

Despite the rapid expansion of in vitro digestion studies on microplastics (MPs), the field remains fragmented due to inconsistent methodologies, varying analytical approaches, and a lack of standardized protocols. These discrepancies hinder cross-study comparisons, complicate risk assessments, and limit the applicability of in vitro models for understanding MP fate and pollutant interactions in the gastrointestinal environment. A comprehensive synthesis is needed to assess progress, identify research gaps, and establish a unified research direction. This review systematically evaluates 85 studies (2020-2024), consolidating key findings and methodological challenges. It examines disparities in digestion protocols, fluid compositions, and exposure conditions, assessing how factors such as pH, enzyme activity, residence time, and temperature shape MPs' behavior and physicochemical transformations. Key findings on bio-corona formation, structural modifications, contaminant bioaccessibility, and interactions with digestive enzymes are synthesized to provide a clearer picture of MP behavior during digestion. With the field remains dominated by studies on polystyrene and polyethylene MPs in human-based models, inconsistencies persist, highlighting the urgent need for standardized methodologies. By addressing these gaps, this review lays a critical foundation for improving reproducibility, advancing standardization efforts, and strengthening exposure assessments, ultimately enhancing our understanding of MP ingestion risks to human health.

Exposure to submicroplastics promotes the progression of nonalcoholic fatty liver disease in ApoE-deficient mice

Microplastics (MPs) pose emerging threats to human health, with growing concerns about liver toxicity and other harmful effects from plastic particles. While aquatic species exhibit hepatic vulnerability to micro/nanoplastics, the role of submicroplastics (100 nm-1 μm) in mammalian non-alcoholic fatty liver disease (NAFLD) progression remains unclear. We investigated the effects of a 12-week exposure to 0.5 μm polystyrene MPs (submicroplastics) in drinking water, administering this to ApoE-deficient mice fed either a chow diet (CD) or a Western diet (WD). Submicroplastics accumulated predominantly in the liver and were excreted in the feces. Histologically, submicroplastics significantly increased NAFLD activity scores, hepatic steatosis (Oil Red O-positive area), and fibrosis (Masson-positive area), with maximal severity in the WD+MPs group. Also, the MPs exposure group had increases in positive areas for F4/80 and inflammatory markers TNF-α, IL-1β and IL-6 expression under both diets. Concurrently, submicroplastics inhibited antioxidant defenses by lowering levels of superoxide dismutase and glutathione, while also increasing the lipid peroxidation marker malondialdehyde. WD-fed mice exhibited pronounced MPs-induced lipid dysregulation, including elevated hepatic triglycerides, total cholesterol, and free fatty acids (FAs). Mechanistically, submicroplastics upregulated FA synthesis regulators (ACC, FASN, SREBP1) while downregulating FA oxidation mediators (CPT1A, ACOX1, PPARα) in the livers under a WD. Our findings demonstrate that chronic submicroplastics-exposure exacerbates the progression of NAFLD in ApoE-deficient mice by disturbing lipid metabolism, enhancing oxidative stress, and amplifying inflammatory responses. This study provides experimental evidence linking environmental plastic pollution to accelerated metabolic liver disease, thereby highlighting the urgent need for plastic exposure control strategies.

Occurrence and environmental consequences of microplastics and nanoplastics from agricultural reuse of wastewater and biosolids in the soil ecosystem: A review

The contamination of soil and groundwater ecosystems by plastic particles (micro- and nanoplastics) was discussed, focusing on wastewater and biosolids recycled into agricultural soils. The impact of these contaminants was critically examined. Livestock (average: 18; min.: 8 - max.: 42 MP/L) and municipal (average: 2226; min: 0.08 - máx: 31,400 MP/L) wastewater, vinasse, and biosolids (>30,000 MP/L) from wastewater treatment plants are the most frequently reported in the literature for their nutritional potential in agricultural reuse. However, aside from municipal wastewater and biosolids, plastic particles in these other matrices are still largely unexplored, posing a potential threat to soil quality due to the limited understanding of their contribution to soil contamination. The particles accumulate in deeper layers, altering the hydraulic conductivity, fertility, organic matter availability, greenhouse gas emissions, and soil fauna and microorganisms. Nanoplastics have a more pronounced impact than microplastics and represent a greater threat. Due to their vertical mobility, nanoplastics have a greater capacity to accumulate in deep layers, including in groundwater. Different from what is observed for microplastics, current detection and quantification methodologies for nanoplastics are broad and nonspecific. It currently considers extensive size ranges (0-5000 μm), making it difficult to accurately identify these compounds, highlighting the need for more suitable methods for detecting nanoplastics. Given the recognized impacts on soil, it is essential to advance studies to ensure the benefits of reusing wastewater and organic soil amendments while effectively eliminating plastic particles from these matrices to prevent critical contamination scenarios.

Identification of microplastics in human tear fluid and meibum: Implications for dry eye disease pathogenesis

Microplastics (MPs) are emerging environmental pollutants that are increasingly being detected in various human tissues. However, their impact on ocular health is underexplored. This study investigated the presence of MPs in tear fluid and meibum of 45 patients with dry eye disease (DED). Various examinations were conducted, including the Schirmer I test, fluorescein tear film break-up time (FBUT) and other dry eye-related assessments. MPs were identified in the tear fluid and meibum and were categorized into five distinct types, with polyethylene (PE) being the most predominant. Notably, PE levels exhibited significant correlations with key DED parameters, such as Schirmer I test scores and FBUT. In in-vitro studies, PE exposure reduced the viability and induced apoptosis of human corneal epithelial cells and conjunctival epithelial cells in a dose-dependent manner. In mouse models, topical exposure to PE drops, which imitate airborne PE exposure, induced typical dry eye signs, reduced goblet cell numbers, and triggered conjunctival inflammation. PE-treated meibomian glands exhibited changes, but these changes were not statistically significant, possibly because of the limited duration of the study. This study is the first to confirm the presence of microplastics (MPs) in human tear fluid and meibum while also offering novel insights into the potential pathogenic effects of airborne MP exposure on ocular health.

Fate of polystyrene micro- and nanoplastics in zebrafish liver cells: Influence of protein corona on transport, oxidative stress, and glycolipid metabolism

Micro- and nanoplastics (MNPs) form protein corona (PC) upon contact with biological fluids, but their impact on the intracellular transport, distribution, and toxicity of MNPs remains unclear. Fetal bovine serum (FBS) and bovine serum albumin (BSA) were used to simulate in vivo environment, this study explored their influence on the transport and toxicity of polystyrene (PS) MNPs in zebrafish liver (ZFL) cells. Results showed PS MNPs were wrapped by proteins into stable complexes. Nanoparticles (NP, 50 nm) and their protein complexes (NP@PC) were internalized by cells within 6 h, with PC formation enhancing NP uptake. NP primarily entered cells through clathrin- and caveolae-mediated endocytosis, while NP@PC via clathrin-mediated pathways. Internalized particles were predominantly in lysosomes where PC degraded and some were also in mitochondria. Eventually, particles were expelled from cells through energy-dependent lysosomal pathways and energy-independent membrane penetration mechanisms. Notably, PC formation limited the clearance of NP. In toxicity, NP had a more severe impact than microplastics (MP, 5 μm). FBS more effectively mitigated PS MNPs-induced reactive oxygen species accumulation, subcellular structural damage, and dysregulation of glycolipid metabolism than BSA did. This study elucidates the modulatory role of PC on biological effects of MNPs, providing safety and risk management strategies.

Omaveloxolone Prevents Polystyrene Microplastic-Induced Ovarian Granulosa Cell Apoptosis via the Keap1/Nrf2/HO-1 Pathway in Rats

Microplastics (MPs) are persistent environmental pollutants that enter the circulatory system and subsequently reduce sperm quantity and quality. However, the influence of polystyrene MPs (PS-MPs) on the ovary and relevant mechanisms remain elusive. Herein, we aimed to examine the impact of PS-MPs on oxidative disorders in ovarian tissues and elucidate the underlying mechanisms. Healthy female rats were treated with different concentrations of 0.5 µm PS-MPs (diluted in deionized H2O) for 90 days. Upon examination of hematoxylin-eosin-stained ovarian tissue sections, the number of growing follicles was reduced in PS-MP-treated rats when compared with that in control rats. Enzyme-linked immunosorbent assays revealed that PS-MP exposure markedly reduced anti-Müllerian hormone (AMH) levels. Treatment with PS-MPs downregulated superoxide dismutase, glutathione, and catalase activities in ovarian tissues while upregulating malondialdehyde levels. Furthermore, exposure to PS-MP blocked the Keap1/Nrf2/HO-1 signal transduction pathway. PS-MPs also triggered apoptosis in the ovarian tissue, as evidenced by increased TUNEL staining and expression levels of cleaved caspase-9, Bax, and Bcl-2. To reactivate the Keap1/Nrf2/HO-1 pathway, rats were co-administered PS-MPs and omaveloxolone (Oma), an Nrf2 activator, for 1 week. We found that Oma could counteract the PS-MP-mediated effects on oxidative disorder, apoptosis, AMH production, and follicle number in rat ovarian tissues. To develop an in vitro model, granulosa cells (GCs) were treated with 10 μM H2O2 for 12 h to induce oxidative stress. H2O2-stimulated GCs exhibited attenuated cell growth and upregulated apoptosis and oxidative stress. Oma administration could ameliorate the H2O2-induced effects in terms of regulating cell viability, apoptosis, and oxidative stress in GCs. In summary, PS-MPs could induce apoptosis and oxidative stress via the Keap1/Nrf2/HO-1 signaling pathway in both rats and GCs.

Interactions of Micro- and Nanoplastics with Biomolecules: From Public Health to Protein Corona Effect and Beyond

Micro- and nanoplastics (M/NPs), as ubiquitous global environmental pollutants, have garnered increasing attention due to their pervasive presence. These particles can interact with biological molecules through various mechanisms, subsequently inducing potential toxic effects on living organisms. This review investigates the hazards of M/NPs and their interactions with biological membranes and proteins, focusing on their interaction mechanisms and potential effects on biomolecular structure and function. Specifically, we summarize the exposure pathways and potential harms of M/NPs, which can enter the human body through ingestion, inhalation, and skin contact, potentially causing toxicity, inflammation responses, oxidative stress, and endocrine disruption. Additionally, we highlight the interaction between M/NPs and biological membranes, which can induce structural changes, including membrane thickening, increased fluidity, and pore formation, thereby compromising membrane integrity and affecting cellular health. Besides, we emphasize the interaction between M/NPs and proteins, suggesting that protein structural changes and corona formation can influence oxidative stress responses and cytotoxicity, thereby impacting cellular functions and viability. Ultimately, suggestions and outlooks for further research are proposed. Overall, this review systematically summarizes current research on the interactions between M/NPs and biomolecules, including their mechanisms and biological effects, providing researchers with a comprehensive understanding of the field.

Study on the toxic effect of seawater-aged microplastics on Philippine curtain clams

This study delved into the impact of aging on the properties of five common microplastic types, including polymethylmethacrylate (PMMA), polystyrene (PS), polyvinyl chloride (PVC), polyethylene (PE), and polypropylene (PP). The aging process significantly altered the particle size distribution: PS, PP, and PMMA underwent a contraction, with average sizes decreasing by 6.8%, 3.2%, and 1.7%, respectively, whereas PE and PVC experienced an expansion, with increases of 3.1% and 1.7%. Notably, aging generally increased the specific surface area of all microplastics by more than 20%, a change that could influence their environmental interactions. Scanning electron microscopy revealed marked surface cracks and depressions in aged PE and PVC, in contrast to minor surface alterations in PS and PMMA. Fourier transform infrared spectroscopy further indicated modifications in the characteristic peaks of aged PMMA, PP, and PE microplastics. Exposure experiments demonstrates that increasing microplastic concentrations from 100 mg/L to 5000 mg/L accelerated mortality rates in clams, with juveniles exhibiting slower mortality onset compared to adults. Prolonged exposure led to rising mortality rates across all groups, suggesting a cumulative toxic effect from long-term microplastic exposure. These findings underscore the environmental ecological risks associated with the altered physicochemical properties of aged microplastics, particularly for the Philippine clam. This study provides an essential insight for advancing our understanding of microplastic behavior and their ecological impacts, highlighting the need for further research to mitigate these environmental threats.

Detection and quantification of microplastics in meconium by pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS)

Microplastics are widely present in the environment and have been found in human biological samples. However, their adverse effects on human remain unclear due to methodological limitations in microplastic analysis. This study aims to develop and validate a Py-GC/MS based analytical method for quantifying 8 typical microplastics in meconium samples. Meconium samples were pretreated via acid digestion, filtration, and analyzed by Py-GC/MS. All 8 microplastics exhibited linear coefficients (R2) exceeding 0.99. Recovery rates (excluding polyethylene terephthalate) ranged from 65.24 % to 114.27 %, with precision values (RSD) of 2.16 % to 14.85 %. Application of this method to 60 meconium samples revealed the presence of all 8 target microplastics, with the concentrations ranging from 1.60 × 10-5 to 1.53 × 103 μg/g and detection rates ranging from 51.67 % to 70.67 %. This method provides a robust technical approach for detecting microplastics in meconium and evaluating associated health risks.

Transcriptome Sequencing and Metabolite Analysis Revealed the Single and Combined Effects of Microplastics and Di-(2-ethylhexyl) Phthalate on Mouse Liver

The widespread use of plastics has led to a substantial increase in plastic waste, resulting in the dissemination of plastic debris throughout ecosystems and posing significant threats to biota. Bis(2-ethylhexyl) phthalate (DEHP), a commonly used plasticizer, enhances plastic flexibility but may also exert subtle toxic effects. This study aimed to investigate the potential toxicological impacts and underlying mechanisms of microplastics (MPs), di-(2-ethylhexyl) phthalate (DEHP), and their combined exposure (MPs + DEHP) on oxidative stress, apoptotic damage, transcriptomic alterations, and metabolic disturbances in mice. The results demonstrated that exposure to MPs, DEHP, and MPs + DEHP impaired the antioxidant defense system and reduced overall antioxidant capacity. Concurrently, all three exposure conditions significantly increased biochemical markers, particularly those associated with liver dysfunction, prompting further analysis of hepatic tissues. Histopathological examination revealed apoptotic damage in hepatocytes. Integrated transcriptomic and metabolomic analyses indicated that exposure to MPs, DEHP, and MPs + DEHP disrupted carbohydrate, amino acid, and lipid metabolism, induced the expression of genes related to hepatocarcinogenesis, and impaired purine metabolism. Moreover, MP and DEHP exposure aggravated hepatic apoptosis and inflammatory responses via activation of the PI3K/AKT signaling pathway, thereby eliciting notable biotoxic effects. These findings provide new scientific evidence regarding the individual and combined toxicological effects of MPs and the plastic additive DEHP on living organisms.

Effects of micro- and nanoplastic exposure on macrophages: a review of molecular and cellular mechanisms

Micro- and nanoplastics (MNPs), pervasive environmental pollutants, contaminate water, soil, air, and the food chain and ultimately accumulate in living organisms. Macrophages are the main immune cells that gather around MNPs and engulf them through the process of phagocytosis. This internalization triggers M1 polarization and the secretion of inflammatory cytokines, including IL-1, IL-18, IL-12, TNF-α, and IFN-γ. Furthermore, MNPs damage mitochondria and lysosomes, causing overactivation of iNOS and excessive production of ROS. This results in cellular stress and induce apoptosis, necroptosis, and, in some cases, metosis in macrophages. The internalization of MNPs also increases the expression of receptors, involving CD36, SR-A, LOX-1, and the macrophage receptor with a collagenous structure (MARCO) while decreasing ABCA-1 and ABCG-1. MNPs in adipose tissue macrophages trigger proinflammatory cytokine secretion, causing adipogenesis, lipid accumulation, insulin resistance, and the secretion of inflammatory cytokines in adipocytes. Various factors influence the rate of MNP internalization by macrophages, including size, charge, and concentration, which affect internalization through passive diffusion. Receptor-mediated phagocytosis of MNPs occurs directly via receptors like T-cell immunoglobulin and mucin domain containing 4 (TIM-4) and MARCO. The attachment of biomolecules, including proteins, antibodies, opsonins, or microbes to MNPs (forming corona structures) promotes indirect receptor-mediated endocytosis, as macrophages possess receptors like TLRs and FcγRIII. MNPs also cause gut dysbiosis, a risk factor for proinflammatory microenvironment and M1 polarization. Here, we review the mechanisms and consequences of MNP macrophage exposure, which is linked to autoimmunity, inflammation, and cardiometabolic syndrome manifestations, including atherosclerosis and obesity, highlighting the immunotoxicity of MNPs.

Dietary exposure to environmental phenols and phthalates in Korean adults: data analysis of the Korean National Environmental Health Survey (KoNEHS) 2018-2020

Environmental phenols and phthalates, endocrine-disrupting chemicals, are linked to dietary intake, highlighting the need to identify sources to prevent exposure-related diseases. This study investigates dietary patterns associated with urinary concentrations of environmental phenols and phthalate metabolites in Korean adults using data from 4201 adults in the Korean National Environmental Health Survey Cycle 4 (2018-2020). Exploratory factor analysis identified three dietary patterns: Western-style, traditional Korean, and seafood-rich. We analyzed metabolites with a ≥80 % detection rate, specifically environmental phenols (BPA, BPF, BPS, TCS, MP, EP, BP) and phthalates (MEHHP, MEOHP, MnBP, MECPP, MBzP, MCPP, MEP, MMP). The Western-style or processed food diet showed a significant negative association with MP (β [95 % CI] = -0.14 [-0.24, -0.03]), but no positive association. The traditional Korean diet showed significant positive associations with TCS (β [95 % CI] = 0.09 [0.02, 0.15]), EP (β [95 % CI] = 0.08 [0.01, 0.16]), BP (β [95 % CI] = 0.09 [0.05, 0.12]), MEHHP (β [95 % CI] = 0.04 [0.003, 0.08]), MECPP (β [95 % CI] = 0.06 [0.02, 0.09]), and MMP (β [95 % CI] = 0.11 [0.06, 0.15]). In comparison, it had a significant negative association with BPS (β [95 % CI] = -0.15 [-0.22, -0.09]). The seafood-rich dietary pattern exhibited a significant negative association with BP (β [95 % CI] = -0.07 [-0.11, -0.03]). Certain dietary patterns, including those traditionally regarded as healthy, may be associated with exposure to environmental phenols and phthalates, highlighting the need for further research to understand dietary sources of exposure before drawing implications for public health guidance.

Synergistic Toxicity of Combined Exposure to Acrylamide and Polystyrene Nanoplastics on the Gut-Liver Axis in Mice

Acrylamide (AA) and nanoplastics (NPs) are common food toxicants. However, their combined toxicity and health risks call for further studies. This study aimed to investigate the combined toxicity of AA and polystyrene NPs (PS-NPs) in mice through drinking water exposure. Co-exposure to AA and PS-NPs aggravated colon and liver damage, including more severe inflammatory infiltration, higher levels of colonic and hepatic pro-inflammatory cytokines, and elevated serum content of lipopolysaccharide and activities of diamine oxidase, alanine aminotransferase, and aspartate aminotransferase compared to single exposures. Co-exposure also significantly downregulated the expression of colonic tight-junction genes ZO-1 and Claudin-5. Metabolomics revealed that co-exposure induced more profound metabolic disorders in the liver, particularly affecting amino acid and carbohydrate metabolism. 16S amplicon sequencing showed that co-exposure caused more drastic gut microbiota dysbiosis, characterized by a decrease in beneficial bacteria (unclassified_f__Oscillospiraceae, Roseburia, UCG-005, Ruminiclostridium, unclassified_o__Clostridia_UCG-014, Fournierella, and Acetatifactor) and an increase in pathogenic bacteria (Eubacterium_xylanophilum_group and Eubacterium_nodatum_group). Correlation analysis indicated a negative correlation between beneficial bacteria and intestinal-liver toxicity indicators and a positive correlation between pathogenic bacteria and these indicators. Overall, our findings showed that AA and PS-NPs exerted synergistic toxicity to the gut-liver axis in mammals, highlighting the higher health risks of their combined ingestion.

Introducing internal allocation factors for assessing aggregate pesticide exposure across multiple pathways and routes

In the health risk assessment of pesticides, methods for external exposure assessment have been well developed. However, quantifying the contribution of various exposure pathways or routes to internal dose remains challenging. This study introduced the internal allocation factor (IAF) for 319 pesticides to investigate the impact of different exposure pathways and routes on chemical distribution within the human body. The IAFs can be calculated from various exposure sources (or pathways), routes, and biological samples. Analysis of different exposure sources revealed that crop exposure generally had the lowest IAF in organs and tissues, indicating a high contribution to the internal dose. The median IAF values for crop exposure in blood, liver, lung, kidney, fat, and muscle were all around 1.05. For three exposure routes of soil pesticide, the results found that IAF values for oral and dermal exposure routes were significantly lower than those for inhalation exposure. When the pesticide concentrations in biological samples are known, IAF can be utilized to back-calculate the pesticide levels in other organs and tissues. The results show that under a single exposure route, the concentration factor varies greatly between organs or tissues due to differences in compositions of human tissues (e.g., water and lipid contents) and pesticide properties (e.g., hydrophilicity and lipophilicity).

Current research development on food contaminants, future risks, regulatory regime and detection technologies: A systematic literature review

Food contaminants pose serious threats to public health, with profound negative impacts on the economy, society, and environment. However, there is a lack of timely and comprehensive reviews on the latest developments in food contaminants and effective measures to prevent contamination, particularly through novel intelligent detection technologies and regulatory regimes. This study addresses this knowledge gap by presenting a timely review of the literature, focusing on current types of food contaminants, advances in detection technologies, emerging risks, and the latest developments in regulatory frameworks. The study reviewed 116 relevant articles published between 2019 and 2024 and conducted a thematic analysis. The food contaminants were classified into three categories: biological, chemical, and physical. The study identified six key drivers of current and future food safety risks: demographic change, economic factors, environmental conditions, geopolitical shifts, consumer priorities, and technological advancements. Findings reveal the uneven understanding of contaminants of emerging concern, future drivers of contaminants of emerging concern, and their impact on the food system, the environment, and human health. These findings highlight the need for future research on systematically identifying and validating the regional differences in food contamination prevention measures and assessing the extent to which these differences impact the effectiveness of prevention, mitigation, and control efforts. The findings also call for more international cooperation in food contamination research and the active involvement of technology partners to facilitate the application of cutting-edge technologies in food contamination detection and control.

Detection of microplastics in the human penis

The proliferation of microplastics (MPs) represents a burgeoning environmental and health crisis. Measuring less than 5 mm in diameter, MPs have infiltrated atmospheric, freshwater, and terrestrial ecosystems, penetrating commonplace consumables like seafood, sea salt, and bottled beverages. Their size and surface area render them susceptible to chemical interactions with physiological fluids and tissues, raising bioaccumulation and toxicity concerns. Human exposure to MPs occurs through ingestion, inhalation, and dermal contact. To date, there is no direct evidence identifying MPs in penile tissue. The objective of this study was to assess for potential aggregation of MPs in penile tissue. Tissue samples were extracted from six individuals who underwent surgery for a multi-component inflatable penile prosthesis (IPP). Samples were obtained from the corpora using Adson forceps before corporotomy dilation and device implantation and placed into cleaned glassware. A control sample was collected and stored in a McKesson specimen plastic container. The tissue fractions were analyzed using the Agilent 8700 Laser Direct Infrared (LDIR) Chemical Imaging System (Agilent Technologies. Moreover, the morphology of the particles was investigated by a Zeiss Merlin Scanning Electron Microscope (SEM), complementing the detection range of LDIR to below 20 µm. MPs via LDIR were identified in 80% of the samples, ranging in size from 20-500 µm. Smaller particles down to 2 µm were detected via SEM. Seven types of MPs were found in the penile tissue, with polyethylene terephthalate (47.8%) and polypropylene (34.7%) being the most prevalent. The detection of MPs in penile tissue raises inquiries on the ramifications of environmental pollutants on sexual health. Our research adds a key dimension to the discussion on man-made pollutants, focusing on MPs in the male reproductive system.

Supramolecular interaction-enhanced green active packaging films: Design and performance of Ca2+-crosslinked carboxymethyl chitosan composite films

Given the environmental challenges caused by petroleum-based plastics, this study developed a novel green carboxymethyl chitosan (CMCS)-based active packaging composite film (CP) through a synergistic strategy of precise Ca2+ coordination cross-linking and small-molecule plasticizing. Based on this strategy, the CP-4.5 film (CaCl2: 7 wt%, DL-3-phenyllactic acid (3-PLA): 4.5 wt%) exhibited exceptional mechanical properties, including high flexibility (Young's modulus: 0.747 GPa; elongation at break: 65.2 %) and high toughness (18.4 MJ m-3). The incorporation of CaCl2 not only occupied voids within the CP film but also increased the physical cross-linking strength and density of the polymer network. This structural reorganization impeded the diffusion of O2 and H2O molecules, reducing oxygen permeability by 85.9 % and water vapor permeability by 57.6 %. Additionally, 3-PLA, functioning as a broad-spectrum antibacterial agent, imparted the CP film with superior antibacterial activity. The CP film exhibited recyclability and repairability, and underwent complete biodegradation within 56 days. Overall, the synergistic effect of CaCl2 and 3-PLA endowed the CP film with superior mechanical properties, barrier properties, antimicrobial activity, and environmental sustainability, effectively mitigating the quality deterioration of refrigerated grass carp fillets during storage, demonstrating the promising potential of the CP film for food packaging applications.

Feasibility of Raman and FTIR spectroscopy for direct microplastic search in the human milk samples: Comparative qualitative study

The ubiquitous presence of microplastic particles encompasses the human tissues and secreta. Unfortunately, the complex biological matrix hampers the proper polymer identification, and harsh purification protocols damage the microplastic particles (MPs), change the specimens frequently used and needed for additional diagnostics, and bias the final result. Moreover, purification of human milk samples is sometimes impossible, as the samples can not be subjected to any chemical pretreatment. Thus, this paper aims to check the feasibility of complementary spectral approaches, namely FTIR (Fourier-transform infrared) and Raman spectroscopy, to the fast scanning of selected MPs presence, in particular polyethylene (PE), and polystyrene (PS), in human milk samples without any previous purification to prevent the change of matrix. Although the proposed approach cannot be used for the quantitative measurement of MPs concentration or the detection of low-size fractions, it is a valuable tool for the preliminary screening of numerous population samples, and some preliminary conclusions can be drawn. One may easily detect the most common MPs and observe their eco-corona. Mapping mode is beneficial for scanning large areas. Furthermore, the spectral methods turned out to be efficient in the milk itself diagnosis, for instance, the monitoring of the fat content. The results were placed in the context of the ongoing broad discussion about MPs interaction with the human body and several possible impact mechanisms.

Detection of microplastics in pterygium tissue: Implications for environmental hazards

PurposeThis study aimed to report a case of microplastics (MPs) detection in a pterygium patient's tissue.Case reportA pterygium specimen was obtained from the right eye of a 43-year-old woman by surgical removal of a recurred pterygium. The number, morphology, and material type of the MPs in pterygium were identified using Raman microscopy and scanning electron microscopy. Ten MPs were detected in the pterygium, which corresponded to polyethylene (PE) (n = 7), polystyrene (PS) (n = 2), and polypropylene (PP) (n = 1). The size of MPs ranged from 5-9 µm (n = 5, PE or PS), 10-19 µm (n = 4, PE), and 50-99 µm (n = 1, PP). All MPs were transparent and irregular fragments.ConclusionsThis study demonstrated the detection of MPs in the pterygium tissue. Our findings suggest that environmental hazards, such as MP, may be commonly exposed to the ocular surface.

The endoplasmic reticulum-mitochondrial crosstalk involved in nanoplastics and di(2-ethylhexyl) phthalate co-exposure induced the damage to mouse mammary epithelial cells

With the extensive use of plastic products, significant amounts of microplastics, nanoplastic particles (NPs), and plasticizers such as Di(2-ethylhexyl) phthalate (DEHP) are continuously released into the environment. However, the toxic effects of NPs alone or in combination with DEHP on mammary glands remain unreported. This study investigates the impacts of NPs and DEHP on the structure and function of mouse mammary epithelial cells and elucidates the underlying molecular mechanisms. We found that co-exposure to NPs and DEHP induced severe pyroptosis, inflammation and oxidative stress in HC11 cells. Co-exposure also caused mitochondrial damage, as evidenced by changes in mitochondrial membrane potential, increase in mitochondrial ROS and inhibition of ATP production. Moreover, NPs and DEHP co-exposure increased the transcriptional levels of endoplasmic reticulum (ER) stress-related genes, activated the inflammation-related NLRP3 signaling pathway, and damaged the cell membrane integrity. Notably, Co-exposure enhanced the ER-mitochondria crosstalk in HC11 cells, as evidenced by the upregulated transcriptional levels of ER Ca2+ channel proteins (Ip3r1, Grp75 and Vdac1), increased mitochondrial Ca2+ levels, and expanded mitochondrial-ER contact areas. In summary, this study revealed that NPs and DEHP co-exposure had the potential to induce pyroptosis and inflammation by enhancing the ER-mitochondria crosstalk, ultimately resulting in injury to mammary glands. These findings would provide some new insights into the molecular mechanisms underlying the toxic effects of NPs and DEHP to mammary glands.

Greywater reuse for irrigation: A critical review of suitability, treatment, and risks

Greywater accounts for approximately 75 % of domestic wastewater and generally contains fewer contaminants than domestic wastewater. Therefore, its treatment and reuse represent a promising approach to supplement irrigation demand. This study comprehensively evaluates the quality characteristics of greywater based on its source, applied treatment methods, and its potential health, environmental, soil, and agricultural impacts. Various physical, chemical, and biological treatment processes have been analysed, with the most commonly employed technologies including membrane bioreactors (MBRs), constructed wetlands, media filtration (sand, activated carbon), disinfection methods (UV, chlorine, ozone), and advanced oxidation processes. The effectiveness of these methods has been assessed concerning the intended reuse application, emphasizing the critical role of disinfection in ensuring safe irrigation use. The health and environmental implications of greywater reuse have been examined, focusing on the risks associated with pathogen contamination, detergent residues, and micropollutants, while also evaluating the efficiency of treatment processes in mitigating these risks. From an environmental perspective, the accumulation of essential nutrients such as nitrogen and phosphorus, the potential for salinity buildup, and alterations in soil microbial balance have been investigated. Regarding soil and agricultural impacts, this study analyzes how greywater reuse influences soil structure (e.g., permeability, infiltration), plant growth responses, and the accumulation of heavy metals. These findings contribute to the development of scientifically grounded recommendations for the safe and sustainable reuse of greywater within water management strategies, promoting its role as an alternative water source for irrigation.

Effects of microplastics and tetracycline induced intestinal damage, intestinal microbiota dysbiosis, and antibiotic resistome: metagenomic analysis in young mice

Microplastics (MPs) and antibiotic tetracycline (TC) are widespread in the environment and constitute emerging combined contaminants. Young individuals are particularly vulnerable to agents that disrupt intestinal health and development. However, the combined effects of MPs and TC remain poorly understood. In this study, we developed a young mouse model exposed to polystyrene MPs, either alone or in combination with TC for 8 weeks to simulate real-life dietary exposure during early life. Our findings revealed that concurrent exposure to MPs and TC caused the most severe intestinal barrier dysfunction driven by inflammatory activation and oxidative imbalance. Moreover, exposure to MPs and TC reduced the abundance of potential probiotics while promoting the growth of opportunistic pathogens. Metagenomic analysis further indicated that co-exposure to MPs and TC enhanced the abundance of bacteria carrying either antibiotic resistance genes (ARGs) or virulence factor genes (VFGs), contributing to the widespread dissemination of potentially harmful genes. Finally, a strong positive correlation was observed between microbiota dysbiosis, ARGs, and VFGs. In general, this study highlighted the hazards of MPs and antibiotics to intestinal health in young mice, which provided a new perspective into the dynamics of pathogens, ARGs, and VFGs in early-life intestinal environments.

Association between microplastics exposure and depressive symptoms in college students

BACKGROUND

Microplastics (MP) are pervasive environmental pollutants that have raised concerns regarding their potential health effects. However, limited studies have investigated the relationship between MP exposure and depression, particularly in college students. Our study aims to examine the association between MP exposure and depressive symptoms in college students.

METHODS

A total of 1420 college students from Jiangsu College of Nursing, China, were included in this cross-sectional study. Depressive symptoms were assessed using the Patient Health Questionnaire-2 (PHQ-2), and MP exposure was estimated based on daily airborne MP concentration and drinking-water MP levels. Multivariate logistic regression models were used to estimate the associations between MP exposure and depressive symptoms.

RESULTS

The prevalence of depressive symptoms among college students was 61.8 %. The median (interquartile range) of total MP exposure was 17403.7 (14174.8-20995.9) particles/day. Airborne MP exposure exhibited positive associations with depressive symptoms, while no significant association was found between drinking-water MP exposure and depressive symptoms. Compared with participants in the lowest quartile of MP exposure, those in the highest quartile of total MP exposure had 38 % higher odds of experiencing depressive symptoms (odds ratio [OR] = 1.38, 95 % CI: 1.21-1.57). When treated as a continuous variable, each 1000-particle increase in total MP exposure was associated with a 7.0 % increase in the odds of depressive symptoms (OR = 1.07, 95 % CI: 1.04-1.10). Stratified analyses indicated that the association between MP exposure and depressive symptoms was stronger among male students and freshmen.

CONCLUSION

This study suggests MP exposure is a contributing factor for depressive symptoms in college students.

Dissection of the potential mechanism of polystyrene microplastic exposure on cardiomyocytes

Microplastics (MPs) are ubiquitous in the global biosphere, have widespread contact with humans, and increase exposure risks. Increasing evidence indicates that MPs exposure increases the risks of cardiovascular disease, however, a comprehensive exploration of the fundamental cellular mechanisms has yet to be undertaken. In this study, we used AC16 cells as a model and exposed them to 10 to 50 μg/mL of polystyrene MPs (PS-MPs), chosen based on the average daily intake and absorption of MPs by humans, to investigate their roles and mechanisms in cell injury. Proteomic analysis reveals that PS-MP-induced differentially expressed genes were enriched on endoplasmic reticulum (ER) stress and autophagy-related entries. The findings from immunofluorescence and western blotting provided further verification of the activation of ER stress by PS-MPs. Although the expression of LC3-II, a canonical autophagy marker was increased, PS-MPs inhibited autophagic flux instead of inducing autophagy. Importantly, ER stress not only contributes to PS-MPs-induced cell injury but also involved in PS-MPs-induced autophagic flux inhibition. Furthermore, the inhibition of autophagy, and the partial restoration of cell injury induced by PS-MPs was achieved through the activation of autophagy. Overall, the results reveal that activation of ER stress and inhibition of autophagic flux plays a significant role in the cell injury caused by PS-MPs in human cardiomyocytes, offering a novel perspective on the mechanism behind MPs-induced cardiomyocyte toxicity.

Quantification of Nanoplastics and Inorganic Nanoparticles via Laser-Induced Breakdown Detection (LIBD)

Nanoparticles with diverse characteristics are difficult to quantify at low concentrations in the water environment (106-109 particles mL-1 for nanoplastics originating from the breakdown of plastic debris) for the evaluation of effective treatment methods. This study examines the sensitivity, or limit of detection (LOD), of laser-induced breakdown detection (LIBD) for the counting of nanoparticles, including nanoplastics. For polystyrene (PS) standards with sizes of 20-400 nm, LIBD shows relatively low LODs (for example, 2 × 106 particles mL-1 for 100 nm particles) compared with turbidity monitoring, UV-vis spectroscopy (both 6 × 108 particles mL-1), and nanoparticle tracking analysis (2 × 107 particles mL-1). For nanoplastics (PS, polypropylene, and polyethylene terephthalate), the detection limits are 104 - 105 particles mL-1, one to two orders of magnitude lower than the PS standards. LIBD can quantify inorganic nanoparticles, such as zeolite, titania, and hematite. The sensitivity increases (i.e., LOD reduces) with increasing particle density, while some particles are prone to artifacts. The low LODs make LIBD a robust technique for counting nanoparticles of various types and sizes, even at the concentrations found in the permeate of membrane-based water treatment systems. Given the high sensitivity, LIBD has the potential to be applied in membrane integrity monitoring and fundamental studies on membrane mechanisms.

Microplastic contamination in artificial tears in South Korea: Potential for direct ocular exposure

PURPOSE

To investigate microplastics (MP) contamination in artificial tear (AT) products.

METHOD

Five hyaluronic acid ATs (two multi-use and three disposable ATs) were used to gauge MP levels in three scenarios: 1) initial drop and remaining liquid after opening the lid upward; 2) remaining liquid after opening the lid downward and discarding two drops; and 3) remaining liquid after opening the lid downward and discarding half of it. Raman spectroscopy was used to identify the quantity, morphological characteristics, and composition of MPs. Scanning electron microscopy/energy dispersive spectroscopy was used to examine the surface traits and elements of MPs and ATs.

RESULTS

MPs were detected in 4 out of 5 ATs in the initial drops, containing 0.50 ± 0.65 particles/30 mL, whereas the remaining solution had 0.75 ± 0.72 particles/30 mL. After discarding two drops, 0.14 ± 0.35 particles/30 mL were present in the remaining solution. No MPs were detected after discarding half drops. Most MPs were transparent (95 %), irregular fragments (55 %) sized 10-20 μm (35 %), and made of polyethylene (95 %). If patients use the first drops of ATs four times a day for a year, individuals can be exposed to 730.0 particles. This exposure can be reduced to 204.4 particles by discarding the first two drops before use.

CONCLUSION

MPs are observed in commercially available ATs, and human eyes may be directly exposed to MPs through the use of ATs.

Promising protective potential of MiR-103a-3p against polystyrene microplastic neurotoxicity in rats

Introduction: Microplastics are ubiquitous environmental pollutants with potential neurotoxic effects that can impair learning and memory. MicroRNAs are essential regulators of a number of physiological and pathological processes, but detailed information on the impact of miRNAs on the neurotoxic effects of microplastics is lacking. Methods: In the present study, polystyrene microplastics (PS-MPs) were administered orally and miR-103a-3p was injected intracerebroventricularly as a treatment for PS-MPs-induced neurotoxicity. Results and Discussion: Performance in the novel object discrimination Y-maze and Barnes maze tests indicated that miR-103a-3p mitigates the deleterious effects of PS-MPs on learning and memory. Oxidative stress, pyroptosis, apoptosis and inflammation induced by PS-MPs were modulated after miR- 103a-3p injection by reducing malondialdehyde, protein carbonyl, nitrite, caspase 3, caspase 1, TNFα, and NLRP3 levels in hippocampal tissue. Our results also showed that miR-103a-3p can reverse the impact of PS-MPs on astrocytic reaction and SIRT1 and BDNF levels. MiR-103a-3p alleviated PS-MPs-induced endoplasmic reticulum (ER) stress through reducing the levels of PERK, CHOP and GRP78. These findings imply that miR-103a-3p exerts a neuroprotective influence against cognitive deficits induced by exposure to PS-MPs. This is achieved by reducing inflammation, oxidative stress, apoptosis and endoplasmic reticulum stress.

Effects of microplastics on chemo-resistance and tumorigenesis of colorectal cancer

Microplastics (MPs) are widely distributed environmental pollutants around the world. Although studies have demonstrated that MPs have adverse effects on human health, the relationship between MPs and tumors remains unclear. The gut is the main site of microplastics absorption, and the function of MPs in the chemoresistance and progression of colorectal cancer (CRC) needs more investigation. Here, we show that MPs exist in human CRC tissues for the first time by using a laser direct infrared chemical imaging system. MPs can cause an increase in CRC incidence in animal models and promote resistance to oxaliplatin. It is illustrated that the uptake of MPs enhances levels of autophagy by activating the mTOR pathway. MPs can also promote the disorder of intestinal flora and intestinal inflammation, serving as an essential component in the onset and advancement of CRC. These results indicated that microplastic pollutants in colorectal cancer could mediate protective autophagy through the mTOR/ULK1 axis, which is one of the new reasons for chemo-resistance in CRC under the background of increasingly serious microplastics pollution. This study identified the adverse effects of MPs on colorectal cancer progression and chemotherapy prognosis, and attempted to block the intake of MPs to propose a novel approach for clinical precision treatment.

Role of microplastics in the tumor microenvironment (Review)

Microplastics (MPs) are pervasive in several ecosystems and have the potential to infiltrate multiple aspects of human life through ingestion, inhalation and dermal exposure, thus eliciting substantial concerns regarding their potential implications for human health. Whilst initial research has documented the effects of MPs on disease development across multiple physiological systems, MPs may also facilitate tumor progression by influencing the tumor microenvironment (TME). This evolving focus underscores the growing interest in the role of MPs in tumorigenesis and their interactions within the TME. In the present review, the relationship between MPs and the TME is comprehensively assessed, providing a detailed analysis of their interactions with tumor cells, stromal cells (including macrophages, fibroblasts and endothelial cells), the extracellular matrix and inflammatory processes. Recommendations for future research directions and strategies to address and reduce microplastic pollution are proposed.

Gestational exposure to polystyrene microplastics incurred placental damage in mice: Insights into metabolic and gene expression disorders

As an emerging environmental pollutant, microplastics have attracted increasing attention to their potential health hazards. However, the current understanding about the toxicity and health implications, especially about developmental toxicity with exposure to microplastics is quite limited. In the current study, we aimed to scrutinize the deleterious effects of polystyrene microplastics (PSMPs) with different sizes (0.1 and 5 μm) on the placenta that plays crucial role in fetal development, following oral exposure during gestational stages. The results showed that two sizes of PSMPs could distribute in mouse placental tissues, and nanosized PSMPs (0.1 μm) exhibited greater capability to penetrate the placenta and deposit in the liver and brain of fetuses than microsized PSMPs (5 μm). Importantly, only 0.1 μm PSMPs induced a decrease in the junctional area, a reduction in the labyrinthine vascularization and an increase in cell apoptosis in the placenta, accompanied by fetal developmental impairments. The results of metabolome and transcriptome uncovered that 0.1 μm PSMP exposure caused changes in metabolic and gene profiles of placental tissues, across multiple pathways such as vascular supply, nutrient absorption and transportation and amino acid metabolism. Overall, our results confirmed that maternal PSMP exposure led to placental damages associated with metabolic and gene expression disorders. This study would provide new insights into the developmental impacts of microplastic consumption during gestation.

Microplastics in agricultural soils: sources, impacts on soil organisms, plants, and humans

Agricultural land has long been regarded as a resource for food production, but over time, the effects of climate change have reduced the ability of soil to produce food efficiently. Nowadays, farmers have moved from traditional to modern techniques of farming. Across the globe, plastic mulching has become widely used on farmlands. According to a few studies, the breakdown of plastic mulches releases microplastics (MPs) into the soil. Despite studies reporting the presence of MPs in soils, there are limited studies on the sources and impacts on soil organisms, plant growth, fruits, and human health. This study evaluated research articles collected from the Web of Science to assess the origin of MP in soil and crops and its effects on soil organisms, plants, and humans. It was observed that MPs come from different sources such as waste water, organic fertilizer, irrigation water, sewage, and sludge. Plastic mulching, which can spread across agricultural fields at varying depths, is the dominant source. Furthermore, it was observed that MPs alter crop quality, reduce the leaf count of wheat, and decrease the root length of crops such as maize, water spinach, black gram, and garden cress. MP can decrease the abundance of soil microarthropods and nematodes, damage the intestinal walls of earthworms, and reduce the feeding and excretion of snails. MP causes liver damage, inflammation, respiratory irritation, and immunological issues. Ultimately, these contaminants (MPs) can transfer and have been detected in fruits and vegetables, which pose adverse effects on human health.

Microplastics induce human kidney development retardation through ATP-mediated glucose metabolism rewiring

Recent research has revealed an accumulation of microplastics (MPs) in the environment and human tissues, giving rise to concerns about their potential toxicity. The kidney is a vital organ responsible for various physiological functions. Early kidney development is crucial for ensuring proper structure and function. Nevertheless, the impact of MPs on renal development is unclear. In the current study, we examined the effect of MPs on nephrogenesis using human kidney organoids. The environmentally relevant concentrations of MPs were applied. Following MP exposure, the kidney organoids exhibited reduced size and abnormal tubular structures. MPs caused an increased level of mitochondrial reactive oxygen species and DNA damage. Transcriptomic and central carbon metabolism analysis data revealed significant alterations in metabolic pathways after MP exposure, with a decrease in glycolysis and an increase in tricarboxylic acid cycle activity. Moreover, glycolysis inhibition was identified as a contributing factor to the reduced size and abnormal tubular structure of the kidney organoids. These results emphasize the negative effects of MPs on renal development through metabolic reprogramming. Our study provides a novel perspective of MP-induced nephron toxicity mechanisms. The affected pathways and metabolites identified here may act as early biomarkers and therapeutic targets for PS-MP-induced renal toxicity.

A review on microplastic fibers and beads in wastewater: The current knowledge on their occurrence, analysis, treatment, and insights on human exposure impact

The persistent presence of microplastic (MP) pollution in conventional wastewater treatment plants (WWTPs) is observed worldwide as they are currently not designed to remove MPs effectively. This pollution eventually re-enters and circulate in the environment, elevating the risks posed to ecosystems and organisms through biotoxicity and ecological destabilization. The most common MP shape in wastewater are microfibers (MFs) yet focused comprehensive studies on MFs is limited. Although not as abundant as MFs, microbeads (MBs) are also an important shape in WWTPs as they were among the first shapes to be targeted for production regulation, highlighting their significant impacts. Targeting these specific shapes are crucial as they represent the foundational components of wastewater MP pollution, and the current lack of these studies hinders our ability to address MP persistence and mitigation and management strategies properly. Therefore, this review aims to present the most up-to-date information on the distribution of MFs and MBs across WWTPs. Specifically, the source, detection, and analysis of MFs and MBs in wastewater, physicochemical characterization and interactions of common MF/MB polymers, and the current efforts to mitigate the production and release of these shaped MPs are summarized. This is the first literature review to focus on MFs and MBs in the aspects of their source, human toxicity, detection, and analysis in wastewater.

Cationic Nanoparticle Networks (CNNs) with Remarkably Efficient, Simultaneous Adsorption of Microplastics and PFAS

Of the past decade, micro/nanoplastics (MP/NP) and per- and polyfluoroalkyl substances (PFAS) have become two of the most pervasive persistent organic pollutants leading to significant accumulation within waterways. Various sorbent materials have been evaluated for PFAS and MP/NP removal, but their simultaneous removal has rarely been explored. Herein, we report a library of polymer-based, cationic nanoparticle networks (CNN) with systematic variation in surface charge density, polymer molecular weight, and nanoparticle size for the removal of anionic MP/NP and PFAS from aqueous solutions. These materials are synthesized in three, one-pot steps starting with polymerization-induced self-assembly (PISA) followed by rapid photocuring and quaternary ammonium salt formation resulting in 3D networks consisting solely of cationic polymer nanoparticles. Our best performing CNN material demonstrated record-high MP removal capacities of Qmax = 1865 mg/g and KF = 58.0 (mg/g)(L/mg)1/n based on Langmuir and Freundlich isotherm model estimations, respectively. Furthermore, the CNN materials demonstrated efficient removal of NPs and MPs in complex water media, such as in seawater and at different pH values, demonstrating the overall material applicability. Finally, simultaneous and efficient removal of MPs and perfluorooctanoic acid (PFOA) was accomplished with similar Qmax (MP) = 478.4 mg/g and Qmax (PFOA) = 134.6 mg/g allowing for dual use.

The coexistence characteristics of microplastics and heavy metals in rhizomes of traditional Chinese medicine in mulch planting area

Rhizomatous traditional Chinese medicines (RTCMs) are widely crushed into powder and swallowed directly as medicine and food or health products to treat various diseases; however, they may contain toxic microplastics (MPs) and heavy metals. Currently, there are no reports on the detection of MPs and MP-heavy metal synergies in RTCMs. In this study, we selected eight representative RTCMs to investigate the abundance, types, sizes, and polymers of MP and heavy metals and to assess the level of contamination of MPs and synergies between MPs and heavy metals in RTCMs. The abundance of MPs in different RTCM ranged from 20.83 to 43.65 items/g. The dominant type was fragment (95.43%), and the dominant particle size was < 0.5 mm (73.72%) in MPs. Polyurethane (PU) (29.21%) and acrylics (ACR 13.53%) were the dominant polymers of MP. MP polymers showed obvious correlations with type and particle size: PU was enriched in 0-50-mm and 100-300-mm fragments, whereas ethylene vinyl acetate and ACR were enriched in 0-30-mm fibers. The heavy metals arsenic (As), lead (Pb), and chromium (Cr) were found to be more susceptible to synergistic contamination with MPs in RTCMs compared to other heavy metals. The estimated daily intake (EDI) of the MPs and heavy metals for RG (Rehmannia glutinosa) and RAY (Rhizoma atractylodis) were higher than others. The results showed that MP pollution is common in RTCMs and carries the potential risk of heavy metal or MP poisoning in humans who consume RTCMs.

Metabolic Reprogramming in Gut Microbiota Exposed to Polystyrene Microplastics

Background: Microplastics (MPs) are small plastic fragments with diameters less than 5 mm in size and are prevalent in everyday essentials and consumables. Large global plastic production has now led to a flooding of MPs in our natural environment. Due to their detrimental impacts on the planet's ecosystems and potentially our health, MPs have emerged as a significant public health concern. In this pilot study, we hypothesize that MPs exposure will negatively affect gut microbiota composition and function, in which metabolic reprogramming plays an important role. Methods: Using in vitro experiments, three bacterial strains (Escherichia coli MG1655, Nissle 1917, and Lactobacillus rhamnosus) were selected to investigate the impacts of MPs exposure. The bacterial strains were individually cultured in an anaerobic chamber and exposed to 1 µm polystyrene MPs at various concentrations (0, 10, 20, 50, 100, and 500 µg/mL) in the culture medium. Results: MPs exposure reduced the growth of all three bacterial strains in a dose-dependent manner. Liquid chromatography mass spectrometry (LC-MS)-based untargeted metabolomics revealed significant differences in multiple metabolic pathways, such as sulfur metabolism and amino sugar and nucleotide sugar metabolism. In addition, we extracted gut microbiota from C57BL/6 mice, and 16S rRNA sequencing results showed a significant upregulation of Lactobacillales and a significant reduction in Erysipelotrichales due to MPs exposure. Furthermore, targeted and untargeted metabolomics corroborated the in vitro results and revealed alterations in microbial tryptophan metabolism and energy producing pathways, such as glycolysis/gluconeogenesis and the pentose phosphate pathway. Conclusions: These findings provide evidence that MPs exposure causes comprehensive changes to healthy gut microbiota, which may also provide insights into the mechanistic effects of MPs exposure in humans.

Polylactic Acid Micro/Nanoplastic Exposure Induces Male Reproductive Toxicity by Disrupting Spermatogenesis and Mitochondrial Dysfunction in Mice

Although considered an "eco-friendly" biodegradable plastic, polylactic acid (PLA) microplastic (PLA-MP) poses a growing concern for human health, yet its effects on male reproductive function remain underexplored. This study investigated the reproductive toxicity of PLA in male mice and its potential mechanisms. To this end, our in vivo and in vitro experiments demonstrated that after degradation in the digestive system, a significant number of PLA-MP-derived nanoparticles could penetrate the blood-testis barrier (BTB) and localize within the spermatogenic microenvironment. Mice exposed to PLA-MPs for a long time exhibited significant reproductive toxicity, evidenced by decreased sperm concentration and motility, increased sperm deformity rates, and disrupted sex hormone levels. Further analysis revealed that PLA impaired BTB, induced mitochondrial dysfunction in the testes, and triggered oxidative stress through excessive ROS production from mitochondria, leading to further testicular damage. Notably, PLA nanoplastics internalized in the mitochondrial sheath and disrupted the mitochondrial structure of sperm, causing dose-dependent impairments in mitochondrial function. Transcriptome analyses further indicated that PLA-MPs disrupted spermatogenesis by inhibiting the expression of key mRNA involved in this process. Collectively, our findings highlight the reproductive toxic effect of biodegradable PLA by damaging BTB and impairing mitochondrial function, which provides insights into the toxicological implications of biodegradable microplastics for mammalian fertility.

Insights into the photoaging behavior of biodegradable and nondegradable microplastics: Spectroscopic and molecular characteristics of dissolved organic matter release

Biodegradable plastics are increasingly used as a potential alternative to nondegradable plastics to tackle plastic pollution. However, recent studies have raised concerns about the ecological risks posed by biodegradable microplastics (MPs), which mainly focused on the risks generated by MPs themselves, neglecting the risks associated with the MPs derived dissolved organic matter (DOM). Therefore, this study selected polylactic acid (PLA) MPs with 50 µm particle size and polystyrene (PS) MPs with 50 µm and 500 nm particle sizes as representatives of biodegradable and nondegradable MPs, respectively, to comparative investigate their photoaging behavior, particularly the differences in DOM release. The results showed that both PLA-MPs and PS-MPs exhibited considerable photoaging under ultraviolet irradiation, accompanied by different color changes (PS turned yellow and PLA turned grayish brown), which were attributed to the different functional groups produced on their surfaces after photoaging (PS-MPs: CO, PLA-MPs: terminal -COOH). Additionally, excitation-emission matrix characterization combined with parallel factor analysis revealed that 50 µm PLA-MPs (16-23 %) released more protein-like low molecular weight DOM during photoaging than that of both 50 µm PS-MPs (7-13 %) and 500 nm PS-MPs (8-18 %). Fourier transform-ion cyclotron resonance-mass spectrometry (FT-ICR-MS) further confirmed that PLA-MPs (41.4 %) produced more unstable DOM easily utilized by microorganisms than that of 50 µm PS-MPs (6.3 %) and 500 nm PS-MPs (7.9 %). These results together suggested that biodegradable MPs with small particle size derived DOM may have a greater impact on microbial activity and carbon cycle than that of nondegradable MPs.

Impact of microplastics exposure on liver health: A comprehensive meta-analysis

Microplastics (MPs) are significant concerns affecting liver health. This is the first comprehensive meta-analysis, evaluating the impact of MPs on liver functions across various animal models, including mice, fish, crabs, and shrimp. Five databases, including PubMed, Embase, Cochrane Central Register of Controlled Trials (CENTRAL), Ovid MEDLINE, and Web of Science, were used to select eligible studies. In all, 70 studies out of 1872 publications were included in the analysis, the impact of MPs on liver enzymes, oxidative stress markers, and inflammatory cytokines were evaluated. Our results revealed significant increases in liver enzymes ALT and AST, oxidative stress markers MDA, and pro-inflammatory cytokines IL-6 and TNF-α, along with a notable reduction in antioxidative enzymes like SOD, CAT, GSH, and GPx. These findings suggest that MPs exposure significantly disrupts liver function by inducing oxidative stress and inflammation. The results underscore the urgent need for targeted environmental policies and further research.

What Gastroenterologists Should Know About Microplastics and Nanoplastics

Global production and widespread use of plastics are increasing dramatically. With current limited recycling and recovery options, microplastics and nanoplastics (MNPs) persist in the natural environment. Due to their ubiquity, human exposure to MNPs is inevitable. In addition to their inherent toxic effects, MNPs can adsorb harmful contaminants and act as vectors for microorganisms, compounding toxicological effects. After entering the body, bioaccumulation occurs in several tissues and organs, including the liver and the gastrointestinal (GI) tract. Proposed clinical effects of MNP absorption include endocrine disruption, alteration of the GI microbiome, and promotion of chronic inflammatory conditions. MNPs can also influence energy metabolism, activate inflammatory pathways, and increase oxidative stress leading to apoptosis. The GI tract is a major site of bioaccumulation for the MNPs in animals and humans. In this editorial, the current understanding of how MNPs are processed is discussed. Discussion on MNP effects on internal microflora, and their proposed role in developing inflammatory bowel diseases, MNP toxicokinetics, and their significance in health and disease are also reviewed. There is a need to understand the impact of MNP exposure on gut health and gut microbiota and identify current research gaps.

Comparative toxicity of microplastics obtained from human consumer products on human cell-based models

Originally developed to conserve natural resources, plastic has become a global pollution issue due to inadequate waste management. The dispersion and weathering of plastic waste in the environment generate micro-sized particles. Despite extensive research on the toxicological effects of pristine polymers, the impact of microplastics (MPs) from consumer plastics is poorly understood. This study investigated the cytotoxic and genotoxic effects of cryo-milled single-use plastic products (fork and cup) on eight cell lines (Caco-2, HEK001, MRC-5, HMEC-1, HepaRG, HMC-3, and T47D) at concentrations from 0.01 to 100 μg/mL. Results showed that 100 μg/mL of MPs did not significantly affect cell viability in Caco-2, HEK001, MRC-5, and T47D. However, HMEC-1 and HMC-3 exhibited decreased viability with 10-100 μg/mL of fork particles, while HMC-3 and HepaRG showed reduced viability with 100 μg/mL of cup particles. Conversely, cup particles increased HMEC-1 proliferation at 0.1-100 μg/mL. Comet assay data indicated that both fork and cup exposure led to elevated DNA fragmentation in HMEC-1 and HMC-3 cells. These findings indicate that MPs from consumer-grade plastics may exhibit cytotoxic and genotoxic effects, with endothelial and microglial cells being particularly susceptible.

The microplastic-crisis: Role of bacteria in fighting microplastic-effects in the digestive system

Plastic particles smaller than 5 mm, referred to as Microplastics, pose health risks, like metabolic, immunological, neurological, reproductive, and carcinogenic effects, after being ingested. Smaller plastic particles are more likely to be absorbed by human cells, with nanoplastics showing higher potential for cellular damage, including DNA fragmentation and altered protein functions. Micro- and nanoplastics (MNPs) affect the gastrointestinal tract by altering the microbial composition, they could influence digestive enzymes, and possibly disrupt mucus layers. In the stomach, they potentially interfere with digestion and barrier functions, while in the intestines, they could increase permeability via inflammation and tissue disruption. MNPs can lead to microbial dysbiosis, leading to gastrointestinal symptoms. By activating inflammatory pathways, altering T cell functions and affecting dendritic cells and macrophages, immune system homeostasis could possibly be disrupted. Probiotics offer potential strategies to alleviate plastic effects, by either degrading plastic particles or directly countering health effects. We compared genetic sequences of probiotics to the genome of known plastic degraders and concluded that no probiotic bacteria could serve the role of plastic degradation. However, probiotics could directly mitigate MNP-health effects. They can restore microbial diversity, enhance the gut barrier, regulate bile acid metabolism, reduce inflammation, regulate insulin balance, and counteract metabolic disruptions. Antioxidative properties protect against lipid peroxidation and MNP-related reproductive system damage. Probiotics can also bind and degrade toxins, like heavy metals and bisphenol A. Additionally, bacteria could be used to aggregate MNPs and reduce their impact. Therefore, probiotics offer a variety of strategies to counter MNP-induced health effects.

The micro(nano)plastics perspective: exploring cancer development and therapy

Microplastics, as an emerging environmental pollutant, have received widespread attention for their potential impact on ecosystems and human health. Microplastics are defined as plastic particles less than 5 millimeters in diameter and can be categorized as primary and secondary microplastics. Primary microplastics usually originate directly from industrial production, while secondary microplastics are formed by the degradation of larger plastic items. Microplastics are capable of triggering cytotoxicity and chronic inflammation, and may promote cancer through mechanisms such as pro-inflammatory responses, oxidative stress and endocrine disruption. In addition, improved microplastics bring new perspectives to cancer therapy, and studies of microplastics as drug carriers are underway, showing potential for high targeting and bioavailability. Although current studies suggest an association between microplastics and certain cancers (e.g., lung, liver, and breast cancers), the long-term effects and specific mechanisms still need to be studied. This review aimed at exploring the carcinogenicity of microplastics and their promising applications in cancer therapy provides important directions for future research and emphasizes the need for multidisciplinary collaboration to address this global health challenge.

Microplastics in the bloodstream can induce cerebral thrombosis by causing cell obstruction and lead to neurobehavioral abnormalities

Human health is being threatened by environmental microplastic (MP) pollution. MPs were detected in the bloodstream and multiple tissues of humans, disrupting the regular physiological processes of organs. Nanoscale plastics can breach the blood-brain barrier, leading to neurotoxic effects. How MPs cause brain functional irregularities remains unclear. This work uses high-depth imaging techniques to investigate the MPs within the brain in vivo. We show that circulating MPs are phagocytosed and lead these cells to obstruction in the capillaries of the brain cortex. These blockages as thrombus formation cause reduced blood flow and neurological abnormalities in mice. Our data reveal a mechanism by which MPs disrupt tissue function indirectly through regulation of cell obstruction and interference with local blood circulation, rather than direct tissue penetration. This revelation offers a lens through which to comprehend the toxicological implications of MPs that invade the bloodstream.

Polystyrene microplastics induce liver fibrosis and lipid deposition in mice through three hub genes revealed by the RNA-seq

Nano- and microplastics (NMPs) have become a serious global environmental threat that causes damage to mammalian organs. In this work, we investigated the potential molecular mechanism underlying the development of liver fibrosis induced by long-term exposure to three different sized polystyrene (PS)-NMPs (80 nm, 0.5 µm and 5 µm) in mice. Liver fibrosis levels were evaluated in mice after chronic exposure to PS-NMPs. Liver inflammation was mainly increased in chronic exposure to 80 nm and 0.5 µm PS-NMPs. Liver lipid deposition was significantly enhanced after PS-NMPs exposure. However, oxidative stress was not changed under PS-NMPs exposure. GO enrichment and KEGG pathway analyses revealed that the DEGs and shared DEGs were mainly enriched in the metabolism of lipids. The mRNA expression levels of genes related to fatty acid oxidation, synthesis and transport were dramatically induced by PS-NMPs exposure. Four hub genes, Acot3, Abcc3, Nr1i3 and Fmo2, were identified by CytoHubba analysis of shared DEGs. The mRNA expression levels of three hub genes, Acot3, Abcc3 and Nr1i3, were significantly augmented under chronic PS-NMPs exposure. Our results suggest that Acot3, Abcc3 and Nr1i3 are potential molecules involved in the development of liver fibrosis under chronic exposure to PS-NMPs.

The abundance and analytical characterization of microplastics in the surface water of Haryana, India

Microplastic (MP) contamination has become a serious environmental concern that affects terrestrial environments, aquatic ecosystems, and human health. The current study assesses the presence, abundance, and morphology of MPs present in the surface water of Rohtak district, Haryana, India, which is rapidly undergoing industrialization. While the morphological studies of MPs were conducted through stereo microscopy and field emission-scanning electron microscopy (FE-SEM), the elemental composition of polymers was analyzed through attenuated total reflectance-Fourier transform infrared (ATR-FTIR). The results revealed that the surface water was significantly contaminated by polyethylene, polypropylene, and polystyrene. Moreover, the abundance of MPs was found to be 16-28 particles/L with an average value of 23 particles/L. Most of the MPs had fibrous morphology with the specifics being, fibers (43.9%), fragments (23.7%), films (17%), and pellets (15.4%). The MPs exhibited a size range of 0.61-4.87 mm, with an average size measured at 2.03 ± 0.04 mm. Also, the MP pollution load index values for the surface water bodies were found to be below 10, indicating a low risk category. Though currently designated as "low risk," it is important that mitigation strategies be brought over at this juncture to further prevent the deterioration of quality of water. Thus, this study not only intends to bring forth the impact of human activities, industrial waste, open waste dumping, and inadequate municipal waste management practices on increasing MP concentration but also highlights the sustainable alternatives and strategies to address this emerging pollutant in urban water systems. For further prevention, the implementation of stringent regulations and on-site plastic waste segregation is a critical component in preventing the disposal of plastic waste in surface water bodies. RESEARCH HIGHLIGHTS: The abundance of MPs was found to be 16-28 particles/L, with an average value of 23 particles/L. The surface water bodies in Rohtak district fall into the hazard categories of low risk with values less than 10. The overall MP concentration in water, across all five areas, based on color was in order: white/transparent (39.1%), black (15%), gray (9.1%), green (8.7%), blue (7.8%), red (7.8%), orange (6.3%), and yellow (6.1%). The dominant polymers were polyethylene (PE) (42%) and polypropylene (41%) as determined by FTIR spectroscopy.

Exploring micro(nano)plastics toxicity from an environmental management perspective: Zebrafish as a vital bridge for assessing potential human health risks

The pollution stemming from the unwarranted utilization and inadequate disposal of plastic products is undergoing rapid escalation. The problem of micro(nano)plastics (MNPs) pollution has recently garnered significant attention, and the issue of human exposure to MNPs cannot be disregarded. However, the present state of research concerning human exposure to MNPs remains in its early stages. The inherent uncertainty and variability associated with MNPs pose significant obstacles to conducting related studies. In order to enhance comprehension of the potential health risks associated with human exposure to MNPs, the utilization of zebrafish as an assessment tool was deemed appropriate. Zebrafish, as one of the most effective toxicological models, assume a significant role in both environmental monitoring and health modeling. This study provides a review of the effects of exposure to MNPs on zebrafish. The findings demonstrate that such exposure can elicit behavioral and physiological alterations in zebrafish, subsequently resulting in a range of toxic consequences. Simultaneously, this study conducts a comparative analysis of the effects of human and zebrafish exposure to MNPs in physiology, exposure environment, and toxicokinetic/toxicodynamic, leveraging the shared characteristics between zebrafish and humans to augment comprehension regarding human exposure to MNPs. Zebrafish model plays a key role in exploring gene expression in human homologous pathways caused by MNPs exposure, and strengthens the understanding of the risk of MNPs exposure. However, physiological, metabolic, and exposure circumstances limit its extrapolation to humans. Furthermore, the reference value and challenge associated with employing zebrafish as a model to discern human health hazards linked to MNPs are assessed, accompanied by suggestions for future research endeavors.

Elucidation on the Interaction Between Transferrin and Tetrachlorobisphenol A Based on Multispectroscopic Analysis, Molecular Docking Technique, and Conformational Studies

Tetrachlorobisphenol A (TCBPA) is a kind of fire retardant extensively used in our life, but it can accumulate in organisms and potentially have toxic effects. Transferrin (TF) is a glycoprotein predominantly present in the blood plasma, serving as an essential mediator for the transportation of iron and other small molecules. In our study, various techniques including multi-spectroscopic and molecular docking were employed to examine the interaction between TCBPA and TF. The TF-TCBPA complex was formed with the binding constant (Ka) in 2.181 ± 0.035 × 104 M-1 at 298 K. ΔH and ΔS were all negative, which means dominant driving forces were van der Waals forces and H-bonds. The secondary structure of TF was changed by TCBPA, resulting in a decline in the α-helix structure, and a corresponding increase in the β-sheet structure. The molecular docking revealed that TCBPA was positioned within a pocket of TF, and it engaged in interactions with some amino acid residues through different forces. Importantly, the interaction between Tyr426/Asp392/His585 and TCBPA implies that TCBPA potentially interferes with the transportation of iron ions in vivo. All of above results indicated the adverse effects of TCBPA on the TF structure and activity should be more attention.

The effects of microplastics exposure on quail's hypothalamus: Neurotransmission disturbance, cytokine imbalance and ROS/TGF-β/Akt/FoxO3a signaling disruption

Microplastics (MPs) have become a major focus of environmental toxicology, raising concerns about their potential adverse effects on animal organs and body systems. As these tiny particles infiltrate ecosystems, they may pose risks to the health of organisms across diverse species. In this study, we attempted to examine the neurotoxic effects of MPs exposure on avian hypothalamus by using an animal model-Japanese quail (Coturnix japonica). The quails of 7-day-old were exposed to 0.02 mg/kg, 0.4 mg/kg and 8 mg/kg polystyrene microplastic (PS-MPs) of environmental relevance for 35 days. The results showed PS-MPs exposure did damages to hypothalamic structure characterized by neuron malformation, irregular arrangement and cellular vacuolation after 5-week exposure. PS-MPs exposure also induced Nissl body reduction and dissolution in the hypothalamus. Moreover, the decrease of acetylcholinesterase (AchE) activity and increasing acetylcholine (Ach) indicated that PS-MPs exposure caused hypothalamic neurotransmission disturbance. PS-MPs exposure also led to neuroinflammation by disrupting the balance between proinflammatory and anti-inflammatory cytokines. Moreover, increasing reactive oxygen species (ROS) and malondialdehyde (MDA) generation with reducing antioxidants indicated PS-MPs led to hypothalamic oxidative stress. Additionally, RNA-Seq analysis found that both transforming growth factor-β (TGF-β) signaling and forkhead box O (FoxO) signaling were disturbed in the hypothalamus by PS-MPs exposure. Especially, the increasing ROS led to TGF-β activation and then induced hypothalamic inflammation by nuclear factor κB (NF-κB) activation. The present study concluded that oxidative stress might be an important mechanistic signaling involved in MPs neurotoxicology.

Mixtures of polystyrene micro and nanoplastics affects fat and glucose metabolism in 3T3-L1 adipocytes and zebrafish larvae

Microplastics (MPs) and nanoplastics (NPs) are pervasive pollutants that pose a hazard to human health. Although most previous studies have investigated the effects of MPs and NPs on digestion, oxidative stress, and inflammation in diverse models, the combined effect of plastic mixtures (PM) containing MPs and NPs on obesity and type 2 diabetes mellitus (T2DM) remains unknown. The hypothesis of our study is to verify the association between PM exposure and clinical features of metabolic diseases such as lipogenesis and insulin resistance. Therefore, we investigated the effects of PM on fat and glucose metabolism in 3T3-L1 cells and high-fat diet (HFD)-induced zebrafish larvae. PM exposure increased cell viability, differentiation, adipogenesis (PPARγ and C/EBPα), and lipogenesis (FAS and SREBP-1c), while it decreased glucose uptake and inhibited insulin signal (IRS1, PI3K, AKT, and GLUT4) expression 3T3-L1 cells. In zebrafish larvae, PM mainly bioaccumulated in the intestine and pancreatic tissue, reducing glucose uptake and increasing body weight and blood glucose compared to controls. Moreover, PM significantly increased adipogenic differentiation (PPARγ) and synthesis (FASN and FABP), proinflammatory cytokines (TNF-α and IL-6), and gluconeogenesis (PCK1 and G6Pase). Conversely, energy and fat metabolism (AMPKα and adiponectin), insulin production (INSα), signaling pathway (IRS1, AKT, and GLUT2), and anti-inflammatory cytokines (IL-10 and IL-4) were suppressed. Overall, this study sheds light on the mechanisms responsible for the detrimental effects of PM exposure on fat and glucose metabolism, providing insights into metabolic disorders, like type 2 diabetes, in both in vitro and in vivo models.